Controlling the gain contribution of background emitters in few-quantum-dot microlasers
Controlling the gain contribution of background emitters in few-quantum-dot microlasers
复制标题
DOI：
10.1088/1367-2630/aaa477
复制
发表时间：
2017-04
影响因子：
3.3
通讯作者：
F. Gericke;Mawussey Segnon;M. Helversen;C. Hopfmann;T. Heindel;Christian Schneider;Sven Höfling
中科院分区：
文献类型：
--
作者：
F. Gericke;Mawussey Segnon;M. Helversen;C. Hopfmann;T. Heindel;Christian Schneider;Sven Höfling
我们提供了实验和理论上的洞察单发射激光效应的量子点（QD）微激光器的背景增益的控制变化下提供的非共振离散增益中心。为此，我们应用了先进的双色激发概念，其中非共振量子点的背景增益贡献可以通过精确平衡在不同波长发射的两个激光器的相对激发功率来连续调谐。以这种方式，通过选择性地激发单个谐振QD和非谐振QD，我们识别出不同的单QD签名的激射特性，并区分单个谐振发射器和可计数数量的非谐振背景发射器对微激光器的光输出的增益贡献。我们的工作解决了一个重要的问题，即单量子点激光在实验可及的系统中是否可行，并表明，对于所研究的微激光器，单量子点增益需要由非共振量子点的背景增益贡献来支持，以达到向激光的过渡。有趣的是，虽然单个QD不能驱动所研究的微柱进入激光，但其对发射的相对贡献可以高达70%，并且它在低于阈值的中间激发机制中主导发射光子的统计。
We provide experimental and theoretical insight into single-emitter lasing effects in a quantum dot (QD)-microlaser under controlled variation of background gain provided by off-resonant discrete gain centers. For that purpose, we apply an advanced two-color excitation concept where the background gain contribution of off-resonant QDs can be continuously tuned by precisely balancing the relative excitation power of two lasers emitting at different wavelengths. In this way, by selectively exciting a single resonant QD and off-resonant QDs, we identify distinct single-QD signatures in the lasing characteristics and distinguish between gain contributions of a single resonant emitter and a countable number of off-resonant background emitters to the optical output of the microlaser. Our work addresses the important question whether single-QD lasing is feasible in experimentally accessible systems and shows that, for the investigated microlaser, the single-QD gain needs to be supported by the background gain contribution of off-resonant QDs to reach the transition to lasing. Interestingly, while a single QD cannot drive the investigated micropillar into lasing, its relative contribution to the emission can be as high as 70% and it dominates the statistics of emitted photons in the intermediate excitation regime below threshold.